Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.6.4.4 (kinesin)
 5,033 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

By making use of DIC video microscopy to monitor microtubule motility we have studied the effect of several MAPs (MAP2, MAP2c, tau) on microtubule-kinesin interactions and microtubule gliding. Of the three MAPs tested, MAP2 interferes most strongly with kinesin-dependent microtubule motility.
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PMID:Effect of MAP2, MAP2c, and tau on kinesin-dependent microtubule motility. 183 64

In this report, we describe an in vitro system for analyzing microtubule-based movements in supernatants of sea urchin egg and embryo homogenates. Using video enhanced DIC microscopy, we have observed bidirectional saltatory particle movements on native taxol-stabilized microtubules assembled in low speed supernatants of Lytechinus egg homogenates, and gliding of these microtubules across a glass surface. A high speed supernatant of soluble proteins, depleted of organelles, microtubules, and their associated proteins supports the gliding of exogenous microtubules and translocation of polystyrene beads along these microtubules. The direction of microtubule gliding has been determined directly by observation of the gliding of flagellar axonemes in which the (+) and (-) ends could be distinguished by biased polar growth of microtubules off the ends. Microtubule gliding is toward the (-) end of the microtubule, is ATP sensitive, and inhibited only by high concentrations of vanadate. These characteristics suggest that the transport complex responsible for microtubule gliding in S2 is kinesin-like. The implications of these molecular interactions for mitosis and other motile events are discussed.
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PMID:Polarized microtubule gliding and particle saltations produced by soluble factors from sea urchin eggs and embryos. 287 41

To understand the mechanism of dynamic instability of microtubule growth and shortening, one needs a means of reliably determining the polarity of the microtubules under investigation. Sea urchin sperm-tail axonemal fragments nucleate the growth of both plus-ended and minus-ended microtubules, but their polarity is not apparent by video-enhanced DIC microscopy. The polarity of a microtubule is usually assessed by observing differences between the rates and lengths of growth and shortening excursions of the two ends. In practice, though, a significant fraction of the population of microtubules displays characteristics intermediate between the average characteristics of either end, thereby escaping classification. Excluding these "intermediate" microtubules from the measured populations introduces bias into the understanding of microtubule dynamic instability. We circumvent this problem by making use of the plus-end directed movement of the microtubule-dependent molecular motor kinesin to determine the polarity of any given microtubule unambiguously. Carboxylated-microspheres coated with kinesin, which are clearly visible by DIC microscopy, were used to determine the polarity of a microtubule. The dynamics were then observed. Kinesin was found to have no marked effect on dynamic instability. By this technique, we show that the distributions of properties that describe microtubule dynamic instability (rates and lengths of growth and shortening as well as frequencies of interconversion between these phases) of plus-ends overlap to a significant extent with those of minus-ends. It is this overlap that obscures the usual classification of the ends. Therefore, models describing microtubule dynamic instability need to incorporate the broad and overlapping range of properties of the two ends.
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PMID:Unambiguous classification of microtubule-ends in vitro: dynamic properties of the plus- and minus-ends. 829 44